How to store number types in exact format to disk

How to store number types in exact format to disk

Hi,

I'm using CORE::Expr as the exact format with kernel Simple_cartisan. Sometimes, I want to store the intermediate results, say, an array of Point_3, in some "exact format" to the disk for later usage or reusing for many times. In other words, the data before I save to the disk and the data after I load again from the disk should be identical so that I can do further computation without losing any precisions.